Washington -- California voters this fall will decide a ballot measure that would require labeling of foods containing genetically engineered material. But the Department of Agriculture is already tied in knots over how to deal with the contamination of organic and conventional foods by biotech crops.

On Monday, a USDA advisory panel will consider a draft plan to compensate farmers whose crops have been contaminated by pollen, seeds or other stray genetically engineered material. The meeting is expected to be contentious, pitting the biotechnology and organic industries against each other.

The draft report acknowledged the difficulty of preventing such material from accidentally entering the food supply and concerns that the purity of traditional seeds may be threatened.

It also cited fears on both sides that official action to address contamination could send a signal to U.S. consumers and export markets in Europe, Japan and elsewhere that the purity and even safety of U.S. crops are suspect.

An official who was not authorized to speak for the record described the current stalemate as "don't ask, don't tell."

Known as AC21, the Advisory Committee on Biotechnology and 21st Century Agriculture consists of representatives from across agriculture. Its current incarnation was created by Agriculture Secretary Tom Vilsack to appease critics after his decision in January 2011 to approve genetically engineered alfalfa, a plant that can spread easily.

Genetically engineered crops are also known as genetically modified organisms, or GMOs. Genetic engineering entails the insertion or deletion of genes, often from different species, into a plant to produce a desired trait. Up to now the chief traits are resistance to insects and herbicides.

U.S. corn 90% biotech

Bioengineered crops dominate U.S. commodities, including 90 percent of U.S. corn. In some states, penetration is all but complete, including 99 percent of the Arkansas cotton crop. Most processed foods contain genetically engineered material.

USDA's organic certification does not permit bioengineered material unless trace amounts show up despite a farmer's best efforts to avoid it. Many food companies do their own testing and have rejected contaminated shipments.

The biotech industry, which includes Monsanto, DuPont and other seed companies, argued that contamination is minimal. Organic growers, they said, get a premium for their crops and should "assume the economic risks associated" with certifying that their crops meet organic standards.

The organic industry said biotech companies should be responsible for containing their own genes and that contamination threatens the right of farmers to choose how to farm.

Vilsack directed the advisory committee to find a way for the two sides to co-exist. The panel has wrestled with the issue for more than a year but remains divided. The draft suggests using taxpayer-subsidized crop insurance to compensate farmers whose crops have been contaminated.

Lisa Bunin, organic policy coordinator for the Center for Food Safety, a Washington nonprofit that opposes genetic engineering, said crop insurance would put the burden of proof and the cost on the victims of contamination. She said the focus should be on preventing contamination, and that California's Proposition 37, which would require the labeling of genetically modified foods, shows that people are "waking up to the realization that there are hidden ingredients in their food."

Compensation is "just a way to hide the effects of ... contamination," Bunin said, calling the draft a "last-ditch attempt by the biotech industry to institutionalize transgenic contamination."

No guarantee

Panel member Isaura Andaluz, head of Cuatro Puertas, a nonprofit heritage seed bank in Albuquerque, issued a blistering critique of the draft earlier this month. Andaluz said she was shocked that the panel's report said "it is not realistic to suggest that commercial seed producers can guarantee zero presence" of genetically engineered material in seed varieties that are organic or not genetically engineered.

If that is true, she wrote, Vilsack's co-existence plan already has failed.

The biotech industry fears that setting a suggested threshold of 0.9 percent engineered content, above which a product would be considered contaminated, would imply a safety limit, falsely signaling to consumers and export markets that bioengineered crops are unsafe.

The draft report said methods have been developed to keep "gene flows" segregated, citing the example of sweet corn grown in fields next to popcorn.

Environmental groups worry, however, that bioengineered crops threaten wild plants, too. Engineered canola and grasses spread easily in storm winds and floods, turning up miles from where crops are planted.

Oversight is split among three agencies, USDA, the Food and Drug Administration and the Environmental Protection Agency. Under a rule developed in 1992 under former Vice President Dan Quayle, bioengineering is presumed safe for food and the environment.